Reland of: cc: Add occlusion checker as a fixed view of occlusion tracker.

cc/layers/picture_layer_impl.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/picture_layer_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 
@@ skipping 460 matching lines @@
 
   should_update_tile_priorities_ = true;
 
   UpdateTilePriorities(occlusion_tracker);
 
   if (layer_tree_impl()->IsPendingTree())
     MarkVisibleResourcesAsRequired();
 }
 
 void PictureLayerImpl::UpdateTilePriorities(
     const OcclusionTracker<LayerImpl>* occlusion_tracker) {

[danakj, 2014/09/09 15:14:39]

even better is pass in the OcclusionChecker instead of an OT*

[vmpstr, 2014/09/09 21:56:56]

Done. I'm passing occlusion to UpdateTiles. That way PLI doesn't nede to worry
about OcclusionTracker (aside from AppendQuads, which will also go away).

   TRACE_EVENT0("cc", "PictureLayerImpl::UpdateTilePriorities");
 
   double current_frame_time_in_seconds =
       (layer_tree_impl()->CurrentBeginFrameArgs().frame_time -
        base::TimeTicks()).InSecondsF();
 
   bool tiling_needs_update = false;
   for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
     if (tilings_->tiling_at(i)->NeedsUpdateForFrameAtTime(
             current_frame_time_in_seconds)) {
       tiling_needs_update = true;
       break;
     }
   }
   if (!tiling_needs_update)
     return;
 
   gfx::Rect visible_rect_in_content_space(
       GetViewportForTilePriorityInContentSpace());
   visible_rect_in_content_space.Intersect(visible_content_rect());
   gfx::Rect visible_layer_rect = gfx::ScaleToEnclosingRect(
       visible_rect_in_content_space, 1.f / contents_scale_x());
   WhichTree tree =
       layer_tree_impl()->IsActiveTree() ? ACTIVE_TREE : PENDING_TREE;
   for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
-    tilings_->tiling_at(i)->UpdateTilePriorities(tree,
-                                                 visible_layer_rect,
-                                                 ideal_contents_scale_,
-                                                 current_frame_time_in_seconds,
-                                                 occlusion_tracker,
-                                                 render_target(),
-                                                 draw_transform());
+    tilings_->tiling_at(i)->UpdateTilePriorities(
+        tree,
+        visible_layer_rect,
+        ideal_contents_scale_,
+        current_frame_time_in_seconds,
+        occlusion_tracker
+            ? occlusion_tracker->GenerateOcclusionChecker(draw_transform())
+            : OcclusionChecker<LayerImpl>());
   }
 
   // Tile priorities were modified.
   layer_tree_impl()->DidModifyTilePriorities();
 }
 
 gfx::Rect PictureLayerImpl::GetViewportForTilePriorityInContentSpace() const {
   // If visible_rect_for_tile_priority_ is empty or
   // viewport_rect_for_tile_priority_ is set to be different from the device
   // viewport, try to inverse project the viewport into layer space and use
@@ skipping 1249 matching lines @@
       PictureLayerTilingSet::TilingRange tiling_range = CurrentTilingRange();
       size_t current_tiling_range_offset = current_tiling_ - tiling_range.start;
       return tiling_range.end - 1 - current_tiling_range_offset;
     }
   }
   NOTREACHED();
   return 0;
 }
 
 }  // namespace cc